In this July 13, 2017 file photo, a law enforcement official escorts Cosmo DiNardo to a vehicle in, Doylestown. DiNardo, who faces four life sentences in prison, was transferred Thursday to a medium-security facility in Luzerne County.

Matt Rourke / Associated Press

Cosmo DiNardo, the admitted killer of four Bucks County men last summer, was transferred early Thursday to a medium-security prison in Northeastern Pennsylvania known for treating mentally ill inmates.

DiNardo, 21, had been held at the state correctional institution in Camp Hill since his sentencing last month to four life terms in prison, according to Amy Worden, a spokeswoman for the state Department of Corrections. On Thursday, he was moved to Retreat, a facility of about 1,000 prisoners in Luzerne County that specializes in treating inmates with "varying levels of severe mental illness," Worden said.

The Bensalem native pleaded guilty last month to the murders of Mark Sturgis, Thomas C. Meo, Dean A. Finocchiaro, and Jimi Patrick in a deal that spared him the death penalty.

Fortunato Perri, DiNardo's criminal defense attorney, did not respond to a request for comment about the transfer.

Prison-reform advocates said Thursday that it's standard procedure for inmates to be sent to Camp Hill after their trials conclude to determine where they'll serve out the remainder of their sentences. It was unclear Thursday why Retreat was chosen for DiNardo.

Mark Potash, Sturgis' father, bristled at the news that DiNardo would be sent to Retreat, saying he was "beyond outraged" at the transfer.

"We were notified this morning that [DiNardo] got transferred to a prison that has contact visits and dog training," Potash said. "I don't know how someone who comes off the street murdering four people gets put into medium security that quickly. Usually, you would think, it takes months to show good behavior to move to a place like that."

On three separate trips, DiNardo lured Sturgis and the other victims to his family's property in Solebury Township with a pledge to sell them marijuana, but instead shot them and buried them in makeshift graves. Their disappearances, and the discovery of their bodies after a multi-day search, drew national attention.

Sean Kratz, DiNardo's cousin and co-defendant, rejected a plea deal last month in a last-minute move that surprised both prosecutors and his defense attorney. County prosecutors have said they plan to pursue the death penalty against Kratz, and may call DiNardo to testify against him.

Meanwhile, Potash said he and the families of the other victims are frustrated with investigators in Bucks County, including District Attorney Matthew Weintraub, and have urged Gov. Wolf's office to investigate whether DiNardo has received any preferential treatment.

Larry King, a spokesman for the Bucks County District Attorney's Office, said he was unable to comment Thursday because of a gag order in the case.